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ChevroletSS 12-07-2012 10:24 AM

Photos of Main Bearings
 
5 Attachment(s)
Hey guys I started taking my 350 roller apart and wanted to get your alls opinion on these main bearings. Do they look normal for having 150,000 miles on them?? Why do they get copper colored??

painted jester 12-07-2012 10:56 AM

Quote:

Originally Posted by ChevroletSS (Post 1620141)
Hey guys I started taking my 350 roller apart and wanted to get your alls opinion on these main bearings. Do they look normal for having 150,000 miles on them?? Why do they get copper colored??

Simple explanation:
The very soft material coating that looks silver is very soft babbit material if the crank makes any friction at all it will give some protection for the crank from damage! your bearings look good for that many miles! You should still at least straight edge the block and check to see if you may need a line bore, and mike your crank and assemble main caps and mike everything!

Jester

MouseFink 12-07-2012 12:22 PM

The copper color is the copper/lead alloy bonding metal between the SAE 1010 steel backing and the lead/tin overlay. The last layer is a flash layer of tin that is used as a dry lubricant. The flash layer of tin is polished off with Scotch Bright by some engine builders before assembly. I have always polished it off and used a good assembly lubricant such as Sealed Power 55-400 or Lubriplate 105 assembly lube.

That is the normal appearance for so-called tri-metal bearings with 100,000 miles on them.

hcompton 12-07-2012 01:01 PM

Yep those are great! Engine was run normally with little abuse and good oil changes.

@mouse did you say you scrathed off the bearing meterial inside of the bearing so they show only copper when you install. You know that lead tin and mostly zinc coating is very important. You are surely doing damage to the crank by running bearing like that. There are several times over the life of an engine that it will not get proper oil to the crank like everytime it starts after setting over night and if oil pressure drops in hard corner or braking. Lots of other reasons its there as well. Not sure how removing it help anything. Surely bad move on a stret car.

MouseFink 12-07-2012 01:30 PM

I rub off the cosmetic tin flash overlay to expose the lead/tin layer. The flash overlay is an electroplated layer of tin on new bearings that only serves as a dry lubricant during assembly. Some bearing manufacturers calls it a "sliding layer" on their tri-metal bearings. Instead of using Scotch Bright, you can also dip the bearings in lacquer thinner and wipe them with a micro-fiber towel.

painted jester 12-07-2012 03:31 PM

Quote:

Originally Posted by MouseFink (Post 1620186)
I rub off the cosmetic tin flash overlay to expose the lead/tin layer. The flash overlay is an electroplated layer of tin on new bearings that only serves as a dry lubricant during assembly. Some bearing manufacturers calls it a "sliding layer" on their tri-metal bearings. Instead of using Scotch Bright, you can also dip the bearings in lacquer thinner and wipe them with a micro-fiber towel.

Mouse fink:thumbup: How old are you? If your a woman don't tell me LOL.
We old farts called it a "slide coat" And if we needed a .001 or .002 we would use a bearing scraper (if needed) and then emery and Crocas cloth them so all bearing inserts had the same crank clearance!!!! Its funny you knew that:mwink: not too many people do it any more and I haven't heard "Slide Layer" in many years!

Years ago blueprinting was more precise maybe because of better machining today? I try to set all my clearances precise.I don't like .001" on one and variations on the rest The crank never touches the inserts during running conditions anyway the oil pressure holds the crank off the inserts and centers it. like you said its a dry lube for inserting and removing the crank dry when miking and crank rotation dry during assembly. But some people think the crank rides right on the inserts LOL. On good blue prints you may assemble and disassemble many times while measuring and setting clearances and you don't want oil and sticky lubes on everything.

You made a really good post:thumbup:

Jester

painted jester 12-07-2012 03:48 PM

H compton:

Even when left for a while the older oils with zink provided a layer of protection because the zinc is a high pressure lubricant that adheres to the metals like crank and bearing material its too bad its been taken out of most oils now! But the new lubricant additives must give good protection (except for the cam).

Jester

trillobite 12-08-2012 05:06 PM

The first and rear main bearings look excellent!

Someone mentioned zddp being taken out of the newer oils, so true, watch out for that. Supposedly they are taking the zddp out to save catylitic converters and energy conservation efforts.

Just for some quick info on that, I recently messaged castrol's "expert" chat, and they said that the Castrol Edge 5W-50 (formulated for classic cars) has 1800ppm of zddp! I did not ask about the phosphorous levels though. For some reason I never thought about the zddp levels protecting the mains.

I am assuming that you pulled the main bearings off since your going to put some fresh ones in, that is an excellent idea.

painted jester 12-08-2012 06:55 PM

The zinc adheres to metal and is a barrier and protects against high pressure wear, Like timing chains & gears, valve stems , wrist pins, ring pressure on cylinders, crank journals, cam lobes, lifters, push rods, rocker arms, Etc. Any metal to metal contact!

New engines don't need as much, they have less metal to metal contact, Belts instead of chains, roller cams, etc.

Jester:thumbup:

hcompton 12-09-2012 01:38 PM

Quote:

Originally Posted by painted jester (Post 1620223)
H compton:

Even when left for a while the older oils with zink provided a layer of protection because the zinc is a high pressure lubricant that adheres to the metals like crank and bearing material its too bad its been taken out of most oils now! But the new lubricant additives must give good protection (except for the cam).

Jester

Yes all true but bearings are made out of a lot more metals than lead and tin. Usally they are zinc coated i was always taught not to even touch it or the caoting will react with the acids in your hands. It is also there for the rest of the life of the crank over years of wear these metals are taken off and that is when the crak begins to fail.

If you never had metal to metal crank contact you would never need to replace the bearings. They would never go bad with just oil touching them. But sadly that is not true they touch on start up and other times in an engines life when oil to that one bearing gets low or over powered and squished out this usally results in spun bearing.

I didnt think new bearings were made with lead in years since its not enviro freindly. When you pay extra for nice high performance bearings you are buying coatings, and they are alot more than flat metal that is the easy part.

1Gary 12-09-2012 02:06 PM

A good read:

Getting Your Bearings: Engine Builder

painted jester 12-09-2012 04:27 PM

Quote:

Originally Posted by hcompton (Post 1620905)
Yes all true but bearings are made out of a lot more metals than lead and tin. Usally they are zinc coated i was always taught not to even touch it or the caoting will react with the acids in your hands. It is also there for the rest of the life of the crank over years of wear these metals are taken off and that is when the crak begins to fail.

If you never had metal to metal crank contact you would never need to replace the bearings. They would never go bad with just oil touching them. But sadly that is not true they touch on start up and other times in an engines life when oil to that one bearing gets low or over powered and squished out this usally results in spun bearing.

I didnt think new bearings were made with lead in years since its not enviro freindly. When you pay extra for nice high performance bearings you are buying coatings, and they are alot more than flat metal that is the easy part.


I dont think I said anything about lead on inserts but I do buy old stock bearings that still contain it like from EGGE still on the shelves and use it for pouring Bobbitt's I just did a Whippet.

# 1: Bearing wear is caused mostly from dirt, carbon, acids, metal particles corrosion from contamination etc, etc, coming through the oil passages not from crank contact! A filter because of the bypass does not filter all the oil during the running of an engine only a percentage! The grooves in old bearings is not from crank contact! If you block the bypass like some do + me on race cars all your oil is filtered all the time , But most filters cant handle flow capacity or pressures!!! A lot of people think oil filters on domestic vehicles, filter all the oil all the time and contaminants cant escape! But they would be very, very wrong!!!!


Your entitled to an opinion wrong or right do what works for you!! But inserts are designed to be modified there is plenty of material to work with for slight increasing of clearances! You don't polish down 1 crank journal to get a .001 to .002 additional Clearance! Its silly!!! To me! It would be like honing a cylinder or deepening the ring land grooves to get your proper ring gap instead of filing the rings! Your the first person I ever heard say that! But to each his own do what works for you.

Jester

painted jester 12-09-2012 04:31 PM

Quote:

Originally Posted by 1Gary (Post 1620915)



Gary LOL:
I just read you post after answering H.comptons post LOL I like the read!! Thanks for posting that :thumbup: If I saw it before I posted compton it would have saved me typing LOL:eek::mwink::D

Jester

ChevroletSS 12-10-2012 05:37 PM

Just wanted to say thanks for the info and help guys. This is off the subject but can anyone recomend any piston rings. Im looking for standard size as I am not getting this block machined at all. This is my do it myself project and the cylinder walls are in great shape. Just gonna use a flex hone brush to freshin them up and to debur the block. And its a chevy 350 if noone got that.

Thanks again for the help. Much appreciated:thumbup:

painted jester 12-10-2012 05:55 PM

If there is a ridge at the top of a cylinder it will probably break your top ring! If you have a not the best looking bore "Cast" file gap rings are more forgiving then chrome, steel molly, or cast molly! I like Hastings, give em a call! make sure what ever ring you choose use a hone stone in the right grit for that particular ring! And don't use a ball hone! If I was you I would micrometer your cylinders to see how the bore is. or take it to a machine shop for a bore measurement and machine hone!

Jester:thumbup:


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